Apparatus for the formation of a metal film

ABSTRACT

An apparatus for forming a metal film, including a reaction vessel for housing a substrate, a precursor feeding device for bubbling a carrier gas through a liquid organometallic complex, vaporizing the organometallic complex, producing a precursor from the vaporized organometallic complex, and feeding the precursor into the reaction vessel, a rotating magnetic field generator for creating a rotating magnetic field in a space above the substrate, and a second plasma generator for generating a plasma from a reducing gas fed into the reaction vessel.

TECHNICAL FIELD

This invention relates to methods and apparatus for the formation of athin noble metal film by a plasma-excited vapor phase growth process.

Moreover, this invention also relates to apparatus and methods forforming a metal film on a substrate surface by a vapor phase growthprocess.

Furthermore, this invention also relates to apparatus for the vaporphase growth of a thin copper film which are useful, for example, in theformation of wiring material films for use in semiconductor devices.

BACKGROUND ART

Conventionally, where it is desired to form a thin noble metal film by avapor phase growth process, such a film has been formed by theutilization of a thermal reaction using a liquid organometallic complex,such as copper hexafluoroacetylacetonato-trimethylvinylsilane[hereinafter referred to as Cu(hfac)(tmvs)], as a raw material.

FIG. 22 is a schematic view of a conventional apparatus 500 for thevapor phase growth of a thin noble metal film. The method for forming athin noble metal film 541 on a substrate 515 by using this apparatus 500is described below. First of all, a liquid raw material 522 comprisingCu(hfac)(tmvs) is contained in a raw material vessel 521, and a carriergas comprising He gas is bubbled therethrough. The raw materialevaporated by bubbling and H₂ for reduction reaction are passed throughflow controllers 503,506 to control their flow rates, respectively, andfed into an inlet vessel 511 having a vaporizer 520 for vaporizing theraw material completely. Thereafter, the resulting precursor 513 isintroduced into a reaction vessel 501 through a perforated plate 512. Asubstrate 515 is disposed beneath perforated plate 512 and placed on aheater 516. In this method, the growth rate and the film quality havebeen improved by controlling the flow rates of raw material 522 and H₂for reduction reaction and the growth temperature.

However, the above-described prior art involves the following threeproblems.

First, since this method is based on the utilization of a thermalreaction induced on the substrate surface by heating substrate 515, ithas been difficult to improve the rate of film growth.

Secondly, the organometallic complex [e.g., Cu(hfac)(tmvs)] used as theraw material is expensive.

Thirdly, since hexafluoroacetylacetonato (hfac) and trimethylvinylsilane(tmvs) attached to Cu in Cu(hfac)(tmvs) remain in the thin Cu film(constituting thin film 541) as impurities, it has been difficult toimprove the film quality.

Moreover, where it is desired to form a metal film (e.g., a thin copperfilm) by a vapor phase growth process, it has been conventional practiceto use a liquid organometallic complex (e.g., copperhexafluoroacetylacetonato-trimethylvinylsilane) as a raw material,dissolve the solid raw material in a solvent, vaporize it, and form afilm on a substrate by the utilization of a thermal reaction.

However, since the prior art involves the formation of a film by theutilization of a thermal reaction, it has been difficult to improve therate of film growth. Moreover, the metal complex used as the rawmaterial is expensive. Furthermore, since hexafluoroacetylacetonato andtrimethylvinylsilane attached to Cu remain in the thin Cu film asimpurities, it has been difficult to improve the film quality.

Furthermore, a thin copper (Cu) film has conventionally been formed byphysical film-forming processes such as vacuum evaporation, ion platingand sputtering, and a chemical vapor phase growth process (CVD process).Among others, the CVD process is widely employed because of itsexcellent surface covering properties.

According to a conventionally known method for the formation of a thincopper film by the CVD process, a liquid organocopper complex such ascopper hexafluoroacetylacetonato-trimethylvinylsilane [hereinafterreferred to as Cu(hfac)(tmvs)] is used as a raw material. This rawmaterial is evaporated, carried to a desired surface of a substrate tobe treated, and thermally decomposed to form a thin copper film on thesubstrate surface.

The above-described method for the formation of a thin copper metal ismore specifically described with reference to FIG. 23 illustrating anapparatus 600 for the vapor phase growth of a thin copper film. First ofall, a substrate 603 to be treated is placed on a flat plate type heater602 within a reaction vessel 601. The gas within the aforesaid reactionvessel 601 is discharged through an exhaust pipe 604 until apredetermined degree of vacuum is reached. Subsequently, a carrier gassuch as He is fed through a pipe 607 a and bubbled through a rawmaterial 605 [i.e., Cu(hfac)(tmvs)] contained in a raw material vessel606. The raw material gas obtained by bubbling and a reducing gas (e.g.,hydrogen) are conducted through pipes 607 b and 607 c, respectively, andfed into a vaporizer 608 disposed in the upper part of the aforesaidreaction vessel 601. The flow rates of the aforesaid raw material gasand hydrogen gas are controlled by flow controllers 609 and 610installed in the respective pipes 607 b and 607 c. After the rawmaterial gas is completely vaporized in the aforesaid vaporizer 608, amixed gas 613 composed of the raw material gas and hydrogen gas isdischarged through a plurality of discharge orifices 612 of a dischargeplate 611 disposed at the bottom of vaporizer 608 so as to travel towardthe aforesaid substrate 603 placed on the aforesaid heater 602. Sincethe aforesaid substrate 603 is heated to a predetermined temperature bythe aforesaid flat plate type heater 602, the aforesaid raw material, orCu(hfac)(tmvs), is thermally decomposed on the surface of substrate 603to form a thin copper film 614 thereon. During this film formation, theoxidation of copper is prevented by the reducing action of hydrogen. Bycontrolling the flow rates of the aforesaid raw material and hydrogenand the heating temperature by heater 602, the rate of copper filmgrowth can be regulated and the film quality can be improved.

However, the above-described conventional method for the formation of athin copper film involves the following three problems.

First, since the above-described method for the formation of a thincopper film is based on the thermal decomposition of vaporizedCu(hfac)(tmvs), it is difficult to improve the rate of film growth.Secondly, the organocopper complex [e.g., Cu(hfac)(tmvs)] used as theraw material is expensive and hence raises the cost of the resultingthin copper film. Thirdly, since hexafluoroacetylacetonato (hfac) andtrimethylvinylsilane (tmvs) are incorporated into the thin copper filmduring its formation and remain therein as impurities, the film qualitytends to be reduced.

The present invention has been made in view of the above-describedcircumstances, and an object thereof is to provide methods and apparatusfor the formation of a thin noble metal film which can achieve a highrate of film growth, can use inexpensive raw materials, and do not allowany impurities to remain in the thin film.

Another object of the present invention is to provide methods andapparatus for the formation of a metal film which can achieve a highrate of film growth, can use inexpensive raw materials, and do not allowany impurities to remain in the film.

Still another object of the present invention is to provide an apparatusfor the vapor phase growth of a thin copper film which uses inexpensivechlorine or hydrogen chloride as a raw material gas, can achieve a highrate of film growth, and can form a thin copper film of good qualitycontaining little residual impurity and having a desired film thickness.

DISCLOSURE OF THE INVENTION

In order to accomplish the above objects, the present invention providesa method for the formation of a metal film which comprises the steps offeeding a raw material gas containing a halogen into an inlet vesselhaving a perforated plate made of metal; converting the raw material gasinto a plasma to generate a raw material gas plasma; etching theperforated plate with the raw material gas plasma to produce a precursorcomposed of the metallic component contained in the perforated plate andthe halogen contained in the raw material gas; converting a reducing gasinto a plasma to generate a reducing gas plasma; after discharging theprecursor from the inlet vessel, passing the precursor through arotating magnetic field so as to cause the precursor to travel toward asubstrate in an accelerated manner; and passing the precursor throughthe reducing gas plasma to remove the halogen from the precursor anddirecting the resulting metallic ion or neutral metal onto the substrateto form a thin metal film on the substrate.

The aforesaid metallic ion is a metal atom which has been ionized by therelease of an electron or electrons, and the aforesaid neutral metal isa metal atom which has not been ionized.

The aforesaid perforated plate is preferably made of Cu or a noble metalsuch as Ag, Au or Pt. For example, when a perforated plate made of Cu isused, Cu_(x)Cl_(y) is produced as the aforesaid precursor. Consequently,Cu ions are directed onto the substrate to form a thin Cu film.

Since two plasmas (i.e., the raw material gas plasma and the reducinggas plasma) are used in this method, the reaction efficiency is markedlyimproved to cause an increase in rate of film growth. Moreover, since achlorine-containing gas is used as the raw material gas and ahydrogen-containing gas is used as the reducing gas, a marked reductionin cost is achieved. Furthermore, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in the thin film can be minimized to form a thin film of highquality.

According to another embodiment of the present invention, the aboveobjects are accomplished by providing a method for the formation of ametal film which comprises the steps of feeding a raw material gascontaining a halogen into an inlet vessel having a perforated plate madeof metal; converting the raw material gas into a plasma to generate araw material gas plasma; etching the perforated plate with the rawmaterial gas plasma to produce a precursor composed of the metalliccomponent contained in the perforated plate and the halogen contained inthe raw material gas; converting a reducing gas into a plasma togenerate a reducing gas plasma; and passing the precursor through thereducing gas plasma to remove the halogen from the precursor anddirecting the resulting metallic ion or neutral metal onto the substrateto form a thin metal film on the substrate.

The aforesaid perforated plate is preferably made of Cu or a noble metalsuch as Ag, Au or Pt. For example, when a perforated plate made of Cu isused, Cu_(x)Cl_(y) is produced as the aforesaid precursor. Consequently,Cu ions are directed onto the substrate to form a thin Cu film.

In order to generate the aforesaid reducing gas plasma, there may beused an electrode to which high-frequency electric power is applied. Forexample, the precursor diffusing toward the aforesaid substrate may bereduced by disposing an electrode opposite to the substrate andgenerating a plasma all over the electrode.

Since two plasmas (i.e., the raw material gas plasma and the reducinggas plasma) are used in this method, the reaction efficiency is markedlyimproved to cause an increase in rate of film growth. Moreover, since ahalogen-containing gas is used as the raw material gas and ahydrogen-containing gas is used as the reducing gas, a marked reductionin cost is achieved. Furthermore, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in the thin film can be minimized to form a thin film of highquality.

According to still another embodiment of the present invention, there isprovided a method for the formation of a metal film which comprises thesteps of feeding a raw material gas containing a halogen into an inletvessel having a perforated plate made of metal; converting the rawmaterial gas into a plasma to generate a raw material gas plasma;etching the perforated plate with the raw material gas plasma to producea precursor composed of the metallic component contained in theperforated plate and the halogen contained in the raw material gas;producing an atomic reducing gas between the perforated plate and asubstrate by heating a reducing gas to a high temperature; and, afterdischarging the precursor from the inlet vessel, passing the precursorthrough the atomic reducing gas to remove the halogen from the precursorand directing the resulting metallic ion or neutral metal onto thesubstrate to form a thin metal film on the substrate.

According to this method, the reaction efficiency is markedly improvedto cause an increase in rate of film growth. Moreover, since ahalogen-containing gas is used as the raw material gas and ahydrogen-containing gas is used as the reducing gas, a marked reductionin cost is achieved. Furthermore, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in the thin film can be minimized to form a thin film of highquality.

According to a further embodiment of the present invention, there isprovided a method for the formation of a metal film which comprises thesteps of bringing a raw material gas containing a halogen into contactwith a hot metallic filament and thereby etching the filament with theraw material gas to produce a precursor composed of the metalliccomponent contained in the filament and the halogen contained in the rawmaterial gas; producing an atomic reducing gas by heating a reducing gasto a high temperature; and passing the precursor through the atomicreducing gas to remove the halogen from the precursor and directing theresulting metallic ion or neutral metal onto a substrate to form a thinmetal film on the substrate.

According to the above-described method, the reaction efficiency ismarkedly improved to cause an increase in rate of film growth. Moreover,since a halogen-containing gas is used as the raw material gas and ahydrogen-containing gas is used as the reducing gas, a marked reductionin cost is achieved. Furthermore, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in the thin film can be minimized to form a thin film of highquality.

According to still a further embodiment of the present invention, thereis provided a method for the formation of a metal film which comprisesthe steps of bringing a raw material gas containing a halogen intocontact with a hot metallic filament and thereby etching the filamentwith the raw material gas to produce a precursor composed of themetallic component contained in the filament and the halogen containedin the raw material gas; utilizing high-frequency electric power for thepurpose of converting a reducing gas into a plasma to generate areducing gas plasma; and passing the precursor through the reducing gasplasma to remove the halogen from the precursor and directing theresulting metallic ion or neutral metal onto a substrate to form a thinmetal film on the substrate.

According to the above-described method, the reaction efficiency ismarkedly improved to cause an increase in rate of film growth. Moreover,since a halogen-containing gas is used as the raw material gas and ahydrogen-containing gas is used as the reducing gas, a marked reductionin cost is achieved. Furthermore, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in the thin film can be minimized to form a thin film of highquality.

In the methods for forming a metal film in accordance with the presentinvention, a halogen gas, a hydrogen halide gas, or a mixed gas composedof these gases is used as the aforesaid raw material gas. For example,there may be used fluorine gas, chlorine gas, bromine gas, iodine gas,and hydrogen halide gases formed by the combination of these halogenswith hydrogen. Among these gases, hydrogen chloride gas has higherreaction efficiency than chlorine gas. Consequently, the use of hydrogenchloride gas can decrease the amount of reducing gas used and hencecause a reduction in cost.

Moreover, the above-described steps extending from the feeding of a rawmaterial gas to the production of a precursor may be replace by a methodcomprising the step of bubbling a carrier gas (e.g., He) through aliquid organometallic complex to evaporate it, and the step ofvaporizing the evaporated organometallic complex in a vaporizer or thelike and introducing the resulting vapor into the reaction vessel.

According to these methods, the reducing gas plasma decomposes theimpurities (e.g., halogen compounds and carbon compounds) contained inthe raw material gas, the amount of impurities remaining in the thinmetal film can be reduced.

According to the present invention, there is also provided an apparatusfor the formation of a metal film which comprises an inlet vesselequipped with a metallic perforated plate having discharge orificesbored therethrough and adapted to receive a raw material gas in itsinternal volume; a first plasma generator for converting the rawmaterial gas received in the inlet vessel into a plasma and therebygenerating a raw material gas plasma; a reaction vessel housing theinlet vessel and a substrate; a rotating magnetic field generator forcreating a rotating magnetic field between the perforated plate and thesubstrate; and a second plasma generator for generating a plasma from areducing gas fed into the reaction vessel.

As the aforesaid rotating magnetic field generator, there may be used,for example, a device comprising a rotating magnetic field coil disposedon the side of the reaction vessel, and a power supply for passing ahigh electric current through the rotating magnetic field coil.

According to another embodiment of the present invention, there isprovided an apparatus for the formation of a metal film which comprisesan inlet vessel equipped with a metallic perforated plate havingdischarge orifices bored therethrough and adapted to receive a rawmaterial gas in its internal volume; a first plasma generator forconverting the raw material gas received in the inlet vessel into aplasma and thereby generating a raw material gas plasma; a reactionvessel housing the inlet vessel and a substrate; and a meshlike,ladderlike or comblike electrode for generating a plasma from a reducinggas fed into the reaction vessel by applying high-frequency electricpower thereto.

By providing the electrode surface with holes or openings, the flux ofthe precursor can be subjected to a reduction reaction uniformly,without preventing the precursor from traveling toward the substrate.

According to still another embodiment of the present invention, there isprovided an apparatus for the formation of a metal film which comprisesan inlet vessel equipped with a metallic perforated plate havingdischarge orifices bored therethrough and adapted to receive a rawmaterial gas in its internal volume; a plasma generator for convertingthe raw material gas received in the inlet vessel into a plasma andthereby generating a raw material gas plasma; a reaction vessel housingthe inlet vessel and a substrate; and a reducing gas heating device forheating a reducing gas fed into the reaction vessel.

As the aforesaid reducing gas heating device, there may preferably beused, for example, a tungsten filament heated to a high temperature bypassing a high electric current therethrough. When a reducing gas ismade to flow through the filament, an atomic reducing gas is produced.

According to a further embodiment of the present invention, there isprovided an apparatus for the formation of a metal film which comprisesa precursor feeding device for bringing a raw material gas into contactwith a hot metallic filament to produce a precursor and feeding theprecursor into a reaction vessel; the reaction vessel housing asubstrate; and a reducing gas heating device for heating a reducing gasfed into the reaction vessel.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film whichcomprises a precursor feeding device for bubbling a carrier gas througha liquid organometallic complex, vaporizing the organometallic complex,producing a precursor from the vaporized organometallic complex, andfeeding the precursor into a reaction vessel; the reaction vesselhousing a substrate; a rotating magnetic field generator for creating arotating magnetic field in a space above the substrate; and a secondplasma generator for generating a plasma from a reducing gas fed intothe reaction vessel.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film whichcomprises a precursor feeding device for bubbling a carrier gas througha liquid organometallic complex, vaporizing the organometallic complex,producing a precursor from the vaporized organometallic complex, andfeeding the precursor into a reaction vessel; the reaction vesselhousing a substrate; and a meshlike, ladderlike or comblike electrodefor generating a plasma from a reducing gas fed into the reaction vesselby applying high-frequency electric power thereto.

By employing these methods and apparatus for the formation of a metalfilm in accordance with the present invention, a thin metal film of highquality showing no precipitation of impurities can be rapidly formed atlow cost.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; a chamber housing the inletvessel and a substrate; first plasma generating means for converting theraw material gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; second plasma generating means for converting ahydrogen-containing reducing gas within the chamber into a plasma togenerate a reducing gas plasma; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor ispassed through the reducing gas plasma within the chamber to removechlorine from the precursor by reduction, without allowing the precursorto deposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; discharge plate heating meansfor heating the discharge plate to a predetermined temperature; achamber housing the inlet vessel and a substrate; first plasmagenerating means for converting the raw material gas within the inletvessel into a plasma to generate a raw material gas plasma, and therebyetching the discharge plate with the raw material gas plasma to producea precursor composed of the metallic component contained in thedischarge plate and the chlorine contained in the raw material gas; andsecond plasma generating means for converting a hydrogen-containingreducing gas within the chamber into a plasma to generate a reducing gasplasma; whereby the precursor, which has been produced by etching theheated discharge plate and is hence easy to reduce, is passed throughthe reducing gas plasma to remove chlorine from the precursor byreduction, and the resulting metallic ion is directed onto the substrateto form a metal film on the substrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; discharge plate heating meansfor heating the discharge plate to a predetermined temperature; achamber housing the inlet vessel and a substrate; first plasmagenerating means for converting the raw material gas within the inletvessel into a plasma to generate a raw material gas plasma, and therebyetching the discharge plate with the raw material gas plasma to producea precursor composed of the metallic component contained in thedischarge plate and the chlorine contained in the raw material gas;second plasma generating means for converting a hydrogen-containingreducing gas within the chamber into a plasma to generate a reducing gasplasma; and chamber heating means for heating the chamber to apredetermined temperature; whereby the precursor, which has beenproduced by etching the heated discharge plate and is hence easy toreduce, is passed through the reducing gas plasma to remove chlorinefrom the precursor by reduction, without allowing the precursor todeposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; a chamber housing the inletvessel and a substrate; first plasma generating means for converting theraw material gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; reducing gas heating means for heating ahydrogen-containing reducing gas to a high temperature and therebyproducing an atomic reducing gas within the chamber between thesubstrate and the discharge plate; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor ispassed through the atomic reducing gas within the chamber to removechlorine from the precursor by reduction, without allowing the precursorto deposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; discharge plate heating meansfor heating the discharge plate to a predetermined temperature; achamber housing the inlet vessel and a substrate; first plasmagenerating means for converting the raw material gas within the inletvessel into a plasma to generate a raw material gas plasma, and therebyetching the discharge plate with the raw material gas plasma to producea precursor composed of the metallic component contained in thedischarge plate and the chlorine contained in the raw material gas; andreducing gas heating means for heating a hydrogen-containing reducinggas to a high temperature and thereby producing an atomic reducing gaswithin the chamber between the substrate and the discharge plate;whereby the precursor, which has been produced by etching the heateddischarge plate and is hence easy to reduce, is passed through theatomic reducing gas to remove chlorine from the precursor by reduction,and the resulting metallic ion is directed onto the substrate to form ametal film on the substrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising an inlet vesselequipped with a metallic discharge plate having a multitude of dischargeorifices bored therethrough and adapted to receive a chlorine-containingraw material gas in its internal volume; discharge plate heating meansfor heating the discharge plate to a predetermined temperature; achamber housing the inlet vessel and a substrate; first plasmagenerating means for converting the raw material gas within the inletvessel into a plasma to generate a raw material gas plasma, and therebyetching the discharge plate with the raw material gas plasma to producea precursor composed of the metallic component contained in thedischarge plate and the chlorine contained in the raw material gas;reducing gas heating means for heating a hydrogen-containing reducinggas to a high temperature and thereby producing an atomic reducing gaswithin the chamber between the substrate and the discharge plate; andchamber heating means for heating the chamber to a predeterminedtemperature; whereby the precursor, which has been produced by etchingthe heated discharge plate and is hence easy to reduce, is passedthrough the atomic reducing gas within the chamber to remove chlorinefrom the precursor by reduction, without allowing the precursor todeposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising precursor feedingmeans for bringing a chlorine-containing raw material gas into contactwith a hot metallic filament to produce a precursor within a chamberhousing a substrate, the precursor being composed of the metalliccomponent contained in the metallic filament and the chlorine containedin the raw material gas; reducing gas heating means for heating ahydrogen-containing reducing gas to a high temperature and therebyproducing an atomic reducing gas within the chamber between thesubstrate and the discharge plate; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor ispassed through the atomic reducing gas within the chamber to removechlorine from the precursor by reduction, without allowing the precursorto deposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate.

In these apparatus, the discharge plate or metallic filament may be madeof copper, so that Cu_(x)Cl_(y) is produced as the aforesaid precursor.Moreover, the discharge plate may be made of copper and thepredetermined temperature to which the discharge plate is heated by thedischarge plate heating means may be in the range of 200 to 800° C.Furthermore, the discharge plate heating means may comprise means forheating the discharge plate by introducing a rare gas into the inletvessel, using the first plasma generating means to generate a rare gasplasma, and applying a voltage so as to cause the rare gas component ionto collide with the discharge plate.

In this case, the predetermined temperature is preferably 600° C. WhenCu_(x)Cl_(y) is produced as the aforesaid precursor, the predeterminedtemperature to which the chamber is heated by the chamber heating meansis preferably about 200° C. In addition to Cu, Ag, Au, Pt, Ti, W and thelike may be used for the discharge plate or metallic filament. As theraw material gas, there may be used chlorine gas, hydrogen chloride gasor a mixed gas composed of these gases.

In order to accomplish the above objects, the present invention alsoprovides a method for the formation of a metal film which comprisesreacting chlorine with a metallic plate within a chamber to produce aprecursor composed of a metallic component and chlorine, removingchlorine from the precursor by reduction, and directing the resultingmetallic ion onto a substrate within the chamber to form a metal film onthe substrate, the method being characterized in that the chamber isheated to a predetermined temperature so as to prevent the precursorfrom depositing on the inner wall of the chamber.

In order to accomplish the above objects, the present invention alsoprovides a method for the formation of a metal film which comprisesreacting chlorine with a metallic plate within a chamber to produce aprecursor composed of a metallic component and chlorine, removingchlorine from the precursor by reduction, and directing the resultingmetallic ion onto a substrate within the chamber to form a metal film onthe substrate, the method being characterized in that the metallic plateis heated to a predetermined temperature so as to make the precursoreasy to reduce.

According to another embodiment of the present invention, the aboveobjects are accomplished by providing a method for the formation of ametal film which comprises reacting chlorine with a metallic platewithin a chamber to produce a precursor composed of a metallic componentand chlorine, removing chlorine from the precursor by reduction, anddirecting the resulting metallic ion onto a substrate within the chamberto form a metal film on the substrate, the method being characterized inthat the chamber is heated to a predetermined temperature so as toprevent the precursor from depositing on the inner wall of the chamberand, moreover, the metallic plate is heated to a predeterminedtemperature so as to make the precursor easy to reduce.

In these methods, the metallic plate may be made of copper, so thatCu_(x)Cl_(y) is produced as the aforesaid precursor.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; a chamber housing the inlet vessel and a substrate;first plasma generating means for converting the raw material gas withinthe inlet vessel into a plasma to generate a raw material gas plasma,and thereby etching the discharge plate with the raw material gas plasmato produce a precursor composed of the metallic component contained inthe discharge plate and the chlorine contained in the raw material gas;second plasma generating means for converting a hydrogen-containingreducing gas within the chamber into a plasma to generate a reducing gasplasma; and chamber heating means for heating the chamber to apredetermined temperature; whereby the precursor is passed through thereducing gas plasma within the chamber to remove chlorine from theprecursor by reduction, without allowing the precursor to deposit on theheated inner wall of the chamber, and the resulting metallic ion isdirected onto the substrate to form a metal film on the substrate. Thus,the precursor is prevented from depositing on the inner wall of thechamber. Consequently, a high rate of film growth can be achieved, aninexpensive raw material can be used, and an apparatus for the formationof a metal film containing no residual impurities can be obtained.Moreover, the necessity of cleaning the inside of the chamberperiodically can be eliminated to cause an improvement in raw materialefficiency and a reduction in running cost.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; discharge plate heating means for heating the dischargeplate to a predetermined temperature; a chamber housing the inlet vesseland a substrate; first plasma generating means for converting the rawmaterial gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; and second plasma generating means for convertinga hydrogen-containing reducing gas within the chamber into a plasma togenerate a reducing gas plasma; whereby the precursor, which has beenproduced by etching the heated discharge plate and is hence easy toreduce, is passed through the reducing gas plasma to remove chlorinefrom the precursor by reduction, and the resulting metallic ion isdirected onto the substrate to form a metal film on the substrate. Thus,a monomeric precursor which can be easily reduced tends to be produced.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover,chlorine can be removed by reduction in a short period of time,resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; discharge plate heating means for heating the dischargeplate to a predetermined temperature; a chamber housing the inlet vesseland a substrate; first plasma generating means for converting the rawmaterial gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; second plasma generating means for converting ahydrogen-containing reducing gas within the chamber into a plasma togenerate a reducing gas plasma; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor, whichhas been produced by etching the heated discharge plate and is henceeasy to reduce, is passed through the reducing gas plasma to removechlorine from the precursor by reduction, without allowing the precursorto deposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate. Thus, the precursor is prevented from depositing on the innerwall of the chamber and, moreover, a monomeric precursor which can beeasily reduced tends to be produced. Consequently, a high rate of filmgrowth can be achieved, an inexpensive raw material can be used, and anapparatus for the formation of a metal film containing no residualimpurities can be obtained. Moreover, the necessity of cleaning theinside of the chamber periodically can be eliminated to cause animprovement in raw material efficiency and a reduction in running cost.Furthermore, chlorine can be removed by reduction in a short period oftime, resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; a chamber housing the inlet vessel and a substrate;first plasma generating means for converting the raw material gas withinthe inlet vessel into a plasma to generate a raw material gas plasma,and thereby etching the discharge plate with the raw material gas plasmato produce a precursor composed of the metallic component contained inthe discharge plate and the chlorine contained in the raw material gas;reducing gas heating means for heating a hydrogen-containing reducinggas to a high temperature and thereby producing an atomic reducing gaswithin the chamber between the substrate and the discharge plate; andchamber heating means for heating the chamber to a predeterminedtemperature; whereby the precursor is passed through the atomic reducinggas within the chamber to remove chlorine from the precursor byreduction, without allowing the precursor to deposit on the heated innerwall of the chamber, and the resulting metallic ion is directed onto thesubstrate to form a metal film on the substrate. Thus, the precursor isprevented from depositing on the inner wall of the chamber.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover, thenecessity of cleaning the inside of the chamber periodically can beeliminated to cause an improvement in raw material efficiency and areduction in running cost.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; discharge plate heating means for heating the dischargeplate to a predetermined temperature; a chamber housing the inlet vesseland a substrate; first plasma generating means for converting the rawmaterial gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; and reducing gas heating means for heating ahydrogen-containing reducing gas to a high temperature and therebyproducing an atomic reducing gas within the chamber between thesubstrate and the discharge plate; whereby the precursor, which has beenproduced by etching the heated discharge plate and is hence easy toreduce, is passed through the atomic reducing gas to remove chlorinefrom the precursor by reduction, and the resulting metallic ion isdirected onto the substrate to form a metal film on the substrate. Thus,a monomeric precursor which can be easily reduced tends to be produced.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover,chlorine can be removed by reduction in a short period of time,resulting in a further improvement in the rate of film growth.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising an inlet vessel equipped with a metallic dischargeplate having a multitude of discharge orifices bored therethrough andadapted to receive a chlorine-containing raw material gas in itsinternal volume; discharge plate heating means for heating the dischargeplate to a predetermined temperature; a chamber housing the inlet vesseland a substrate; first plasma generating means for converting the rawmaterial gas within the inlet vessel into a plasma to generate a rawmaterial gas plasma, and thereby etching the discharge plate with theraw material gas plasma to produce a precursor composed of the metalliccomponent contained in the discharge plate and the chlorine contained inthe raw material gas; reducing gas heating means for heating ahydrogen-containing reducing gas to a high temperature and therebyproducing an atomic reducing gas within the chamber between thesubstrate and the discharge plate; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor, whichhas been produced by etching the heated discharge plate and is henceeasy to reduce, is passed through the atomic reducing gas within thechamber to remove chlorine from the precursor by reduction, withoutallowing the precursor to deposit on the heated inner wall of thechamber, and the resulting metallic ion is directed onto the substrateto form a metal film on the substrate. Thus, the precursor is preventedfrom depositing on the inner wall of the chamber and, moreover, amonomeric precursor which can be easily reduced tends to be produced.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover, thenecessity of cleaning the inside of the chamber periodically can beeliminated to cause an improvement in raw material efficiency and areduction in running cost. Furthermore, chlorine can be removed byreduction in a short period of time, resulting in a further improvementin the rate of film growth.

According to still a further embodiment of the present invention, theabove objects are accomplished by providing an apparatus for theformation of a metal film, the apparatus comprising precursor feedingmeans for bringing a chlorine-containing raw material gas into contactwith a hot metallic filament to produce a precursor within a chamberhousing a substrate, the precursor being composed of the metalliccomponent contained in the metallic filament and the chlorine containedin the raw material gas; reducing gas heating means for heating ahydrogen-containing reducing gas to a high temperature and therebyproducing an atomic reducing gas within the chamber between thesubstrate and the discharge plate; and chamber heating means for heatingthe chamber to a predetermined temperature; whereby the precursor ispassed through the atomic reducing gas within the chamber to removechlorine from the precursor by reduction, without allowing the precursorto deposit on the heated inner wall of the chamber, and the resultingmetallic ion is directed onto the substrate to form a metal film on thesubstrate. Thus, the precursor is prevented from depositing on the innerwall of the chamber. Consequently, a high rate of film growth can beachieved, an inexpensive raw material can be used, and an apparatus forthe formation of a metal film containing no residual impurities can beobtained. Moreover, the necessity of cleaning the inside of the chamberperiodically can be eliminated to cause an improvement in raw materialefficiency and a reduction in running cost.

According to still a further embodiment of the present invention, thereis provided a method for the formation of a metal film which comprisesreacting chlorine with a metallic plate within a chamber to produce aprecursor composed of a metallic component and chlorine, removingchlorine from the precursor by reduction, and directing the resultingmetallic ion onto a substrate within the chamber to form a metal film onthe substrate, the method being characterized in that the chamber isheated to a predetermined temperature so as to prevent the precursorfrom depositing on the inner wall of the chamber. Thus, the precursor isprevented from depositing on the inner wall of the chamber.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover, thenecessity of cleaning the inside of the chamber periodically can beeliminated to cause an improvement in raw material efficiency and areduction in running cost.

According to still a further embodiment of the present invention, thereis provided a method for the formation of a metal film which comprisesreacting chlorine with a metallic plate within a chamber to produce aprecursor composed of a metallic component and chlorine, removingchlorine from the precursor by reduction, and directing the resultingmetallic ion onto a substrate within the chamber to form a metal film onthe substrate, the method being characterized in that the metallic plateis heated to a predetermined temperature so as to make the precursoreasy to reduce. Thus, a monomeric precursor which can be easily reducedtends to be produced. Consequently, a high rate of film growth can beachieved, an inexpensive raw material can be used, and an apparatus forthe formation of a metal film containing no residual impurities can beobtained. Moreover, chlorine can be removed by reduction in a shortperiod of time, resulting in a further improvement in the rate of filmgrowth.

According to still a further embodiment of the present invention, thereis provided a method for the formation of a metal film which comprisesreacting chlorine with a metallic plate within a chamber to produce aprecursor composed of a metallic component and chlorine, removingchlorine from the precursor by reduction, and directing the resultingmetallic ion onto a substrate within the chamber to form a metal film onthe substrate, the method being characterized in that the chamber isheated to a predetermined temperature so as to prevent the precursorfrom depositing on the inner wall of the chamber and, moreover, themetallic plate is heated to a predetermined temperature so as to makethe precursor easy to reduce. Thus, the precursor is prevented fromdepositing on the inner wall of the chamber and, moreover, a monomericprecursor which can be easily reduced tends to be produced.Consequently, a high rate of film growth can be achieved, an inexpensiveraw material can be used, and an apparatus for the formation of a metalfilm containing no residual impurities can be obtained. Moreover, thenecessity of cleaning the inside of the chamber periodically can beeliminated to cause an improvement in raw material efficiency and areduction in running cost. Furthermore, chlorine can be removed byreduction in a short period of time, resulting in a further improvementin the rate of film growth.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising:

a reaction vessel in which a substrate to be treated is placed;

an inlet vessel disposed within the reaction vessel and equipped with acopper discharge plate having a plurality of discharge orifices boredtherethrough;

temperature control means attached to the copper discharge plate;

a raw material gas feed pipe inserted into the inlet vessel for feedingchlorine or hydrogen chloride;

plasma generating means for generating a plasma of chlorine or hydrogenchloride within the inlet vessel;

atomic reducing gas producing means for producing an atomic reducing gaswithin the reaction vessel, at least in the neighborhood of thesubstrate to be treated; and

evacuation means for evacuating any gas from the reaction vessel and theinlet vessel.

According to still a further embodiment of the present invention, thereis provided an apparatus for the formation of a metal film, theapparatus comprising:

a reaction vessel in which a substrate to be treated is placed;

a raw material gas feed pipe inserted into the inlet vessel for feedingchlorine or hydrogen chloride;

a spiral tube attached to the inner end of the raw material gas feedpipe, having a raw material gas flow passage whose inner surface is madeof copper, and equipped with a heating element;

atomic reducing gas producing means for producing an atomic reducing gaswithin the reaction vessel, at least in the neighborhood of thesubstrate to be treated; and

evacuation means for evacuating any gas from the reaction vessel and theraw material gas flow passage.

As specifically described above, the present invention makes it possibleto achieve a high rate of film growth while using inexpensive chlorineor hydrogen chloride as a raw material gas, and to form a thin copperfilm of good quality containing little residual impurities and having adesired film thickness, with good reproducibility. Thus, the presentinvention can provide an apparatus for the vapor phase growth of a thincopper film which is useful, for example, in the formation of wiringmaterial films for use in semiconductor devices and liquid crystaldisplays.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a plasma-excited vapor phase growthapparatus for use in a first embodiment of the present invention;

FIG. 2 is a schematic view of a plasma-excited vapor phase growthapparatus for use in a second embodiment of the present invention;

FIG. 3 is a schematic view of a plasma-excited vapor phase growthapparatus for use in a third embodiment of the present invention;

FIG. 4 is a schematic view of a plasma-excited vapor phase growthapparatus for use in a fourth embodiment of the present invention;

FIG. 5 is a plan view of a meshlike electrode for use in the fourthembodiment of the present invention;

FIG. 6 is a plan view of a ladderlike electrode for use in the fourthembodiment of the present invention;

FIG. 7 is a plan view of a comblike electrode for use in the fourthembodiment of the present invention;

FIG. 8 is a plan view of a punching board type electrode for use in thefourth embodiment of the present invention;

FIG. 9 is a schematic view of a plasma-excited vapor phase growthapparatus for use in a fifth embodiment of the present invention;

FIG. 10 is a schematic side view of an apparatus for the formation of ametal film in accordance with a sixth embodiment of the presentinvention;

FIG. 11 is a schematic side view of an apparatus for the formation of ametal film in accordance with a seventh embodiment of the presentinvention;

FIG. 12 is a schematic side view of an apparatus for the formation of ametal film in accordance with an eighth embodiment of the presentinvention;

FIG. 13 is a schematic side view of an apparatus for the formation of ametal film in accordance with a ninth embodiment of the presentinvention;

FIG. 14 is a schematic side view of an apparatus for the formation of ametal film in accordance with a tenth embodiment of the presentinvention;

FIG. 15 is a schematic side view of an apparatus for the formation of ametal film in accordance with an eleventh embodiment of the presentinvention;

FIG. 16 is a schematic side view of an apparatus for the formation of ametal film in accordance with a twelfth embodiment of the presentinvention;

FIG. 17 is a schematic sectional view of an apparatus for the vaporphase growth of a thin copper film in accordance with a thirteenthembodiment of the present invention;

FIG. 18 is a plan view of the copper discharge plate incorporated in thevapor phase growth apparatus of FIG. 17;

FIG. 19 is a schematic sectional view of an apparatus for the vaporphase growth of a thin copper film in accordance with a fourteenthembodiment of the present invention;

FIG. 20 is a view of one form of the spiral tube incorporated in thevapor phase growth apparatus of FIG. 19;

FIG. 21 is a view of another form of the spiral tube incorporated in thevapor phase growth apparatus of FIG. 19;

FIG. 22 is a schematic view of a conventional apparatus for the vaporphase growth of a thin noble metal film; and

FIG. 23 is a schematic sectional view of a conventional apparatus forthe vapor phase growth of a thin copper film.

BEST MODE FOR CARRYING OUT THE INVENTION

Various embodiments of the present invention will be specificallydescribed hereinbelow with reference to the accompanying drawings.

First Embodiment

FIG. 1 is a schematic view of a plasma-excited vapor phase growthapparatus for the formation of a thin noble metal film in accordancewith a first embodiment of the present invention.

This plasma-excited vapor phase growth apparatus 51 includes a reactionvessel 1 formed into the shape of a box; first and second plasmagenerators 52,53 disposed on the upper and lower sides of reactionvessel 1; and a rotating magnetic field coil 4, 4 disposed on the sideof reaction vessel 1.

Moreover, an inlet vessel 11 for receiving a raw material gas 55 isdisposed in the upper part of the aforesaid reaction vessel 1. A flowcontroller 3 and a nozzle 2 are connected to the sidewall of inletvessel 11, and a perforated plate 12 made of Cu and having a pluralityof holes 12 a bored therethrough is disposed at the bottom thereof.Furthermore, rotating magnetic field coil 4, 4 disposed on the side ofreaction vessel 1 creates a rotating magnetic field in the lower part ofreaction vessel 1, and this rotating magnetic field causes a metal suchas Cu to receive a force directed toward a substrate 15 and therebytravel in an accelerated manner. In the lowermost part of reactionvessel 1, a heater 16 is disposed so as to be spaced from perforatedplate 12, and substrate 15 is placed on this heater 16. At the lower endof reaction vessel 1 and below rotating magnetic field coil 4, areducing gas flow controller 6 and a reducing gas inlet nozzle 5 aredisposed in order to feed a reducing gas 60 comprising hydrogen gas intothe interior of reaction vessel 1. First plasma generator 52 consists ofan insulating plate 9 disposed on the top surface 58 of reaction vessel1, a first plasma antenna 8 disposed on insulating plate 9, and a firstplasma power supply 7. Second plasma generator 53 has the sameconstruction as first plasma generator 52. The bottom wall 56 ofreaction vessel 1 has an exhaust port 57 bored therethrough.

Now, the operation of plasma-excited vapor phase growth apparatus 51having the above-described construction is described below.

First of all, Cl₂ gas used as raw material gas 55 is passed through flowcontroller 3 in order to control its flow rate, and then introduced intoinlet vessel 11 through nozzle 2. Subsequently, the raw material gascomprising Cl₂ gas is converted into a plasma by means of first plasmaantenna 8 which is energized by first plasma power supply 7, so that araw material gas plasma 10 comprising Cl₂ plasma is generated withininlet vessel 11. Since the material of perforated plate 12 contains Cu,this Cl₂ plasma actively causes an etching reaction of perforated plate12 made of Cu, resulting in the production of a precursor (Cu_(x)Cl_(y))13. This precursor (Cu_(x)Cl_(y)) 13 is discharged downward through theplurality of holes 12 a of perforated plate 12. Thereafter, under theaction of the rotating magnetic field created by rotating magnetic fieldcoil 4,4, precursor 13 is accelerated and conveyed toward substrate 15placed on heater 16. Immediately before precursor 13 arrives atsubstrate 15, it passes through a reducing gas plasma 14 comprising H₂plasma produced by means of second plasma antenna 18 which is energizedby second plasma power supply 19. Thus, the aforesaid precursor 13undergoes a reduction reaction with atomic hydrogen to form a thin Cufilm 62 on substrate 15. The extent to which this thin Cu film 62 isformed depends on the uniformity of the rotating magnetic field.

Alternatively, HCl gas may be used as the aforesaid raw material gas 55.In this case, HCl plasma is produced as raw material gas plasma 10, butprecursor 13 produced by an etching reaction of perforated plate 12 madeof Cu is Cu_(x)Cl_(y). Accordingly, raw material gas 55 may comprise anygas containing chlorine, and a mixed gas composed of HCl gas and Cl₂ gasmay also be used. The extent to which a thin film can be stably formeddepends on the uniformity of the rotating magnetic field.

Second Embodiment

FIG. 2 is a schematic view of a plasma-excited vapor phase growthapparatus 65 for the formation of a thin noble metal film in accordancewith a second embodiment of the present invention. Since some componentsof this apparatus 65 have the same structure as those of plasma-excitedvapor phase growth apparatus 51 used in the above-described firstembodiment, these components are designated by the same referencenumerals and the explanation thereof is omitted.

Plasma-excited vapor phase growth apparatus 65 used in the secondembodiment includes a reaction vessel 1 formed into the shape of a box;a first plasma generator 52 disposed on the upper side of reactionvessel 1; and a reducing gas heating device 66 for heating a reducinggas (e.g., hydrogen gas) 55 to produce an atomic gas. When compared withplasma-excited vapor phase growth apparatus 51 used in theabove-described first embodiment, this plasma-excited vapor phase growthapparatus 65 differs in having reducing gas heating device 66.

This reducing gas heating device 66 consists of a reducing gas flowcontroller 6, a reducing gas inlet nozzle 5 attached thereto, and atungsten filament disposed within reducing gas inlet nozzle 5. The endsof the tungsten filament are connected to a direct-current power supply24.

The operation of plasma-excited vapor phase growth apparatus 65 havingthe above-described construction is described below.

First of all, Cl₂ gas used as raw material gas 55 is passed through flowcontroller 3 in order to control its flow rate, and then introduced intoinlet vessel 11 through nozzle 2. Thus, the Cl₂ gas is converted into aplasma by means of plasma antenna 8 which is energized by plasma powersupply 7, so that a raw material gas plasma 10 comprising Cl₂ plasma isgenerated. This Cl₂ plasma actively causes an etching reaction ofperforated plate 12 made of Cu, resulting in the production of aprecursor (Cu_(x)Cl_(y)) 13 within inlet vessel 11. This precursor(Cu_(x)Cl_(y)) 13 is discharged downward through the plurality of holes12 a of perforated plate 12. Immediately before precursor 13 arrives atsubstrate 15, a reducing gas 60 comprising H₂ gas is passed throughreducing gas flow controller 6 in order to control its flow rate,tungsten filament 23 is heated to 1,800° C. by means of direct-currentpower supply 24 to produce an atomic reducing gas 25 comprising atomichydrogen, and this atomic reducing gas 25 is injected into reactionvessel 1 through reducing gas inlet nozzle 5. Thus, precursor 13undergoes a reduction reaction with atomic hydrogen to form a thin Cufilm 62 on substrate 15.

Alternatively, HCl gas may be used as the aforesaid raw material gas 55.In this case, HCl plasma is produced as raw material gas plasma 10, butprecursor 13 produced by an etching reaction of perforated plate 12 madeof Cu is Cu_(x)Cl_(y). Accordingly, raw material gas 55 may comprise anygas containing chlorine, and a mixed gas composed of HCl gas and Cl₂ gasmay also be used.

Since atomic reducing gas 25 comprising atomic hydrogen can be fedsimply by use of reducing gas inlet nozzle 5 which permits a relativelyflexible arrangement, a film having an area up to about 50 mm×50 mm canbe stably formed.

Third Embodiment

FIG. 3 is a schematic view of a plasma-excited vapor phase growthapparatus 70 for the formation of a thin noble metal film in accordancewith a third embodiment of the present invention. Since some componentsof this apparatus 70 have the same structure as those of plasma-excitedvapor phase growth apparatus 51,65 used in the above-described first andsecond embodiments, these components are designated by the samereference numerals and the explanation thereof is omitted.

Plasma-excited vapor phase growth apparatus 70 used in the thirdembodiment includes a reaction vessel 1 formed into the shape of a box;a raw material gas heating device 71 disposed in the upper part ofreaction vessel 1; and a reducing gas heating device 66 disposed in theupper part of reaction vessel 1. When compared with plasma-excited vaporphase growth apparatus 65 used in the above-described second embodiment,this plasma-excited vapor phase growth apparatus 70 differs in havingraw material gas heating device 71.

This raw material gas heating device 71 consists of a flow controller 3,a nozzle 2 attached thereto, and a copper filament comprising severalturns of copper wire and disposed within nozzle 2. The ends of copperfilament 26 are connected to a direct-current power supply 27.

The operation of plasma-excited vapor phase growth apparatus 70 havingthe above-described construction is described below.

First of all, Cl₂ gas used as raw material gas 55 is passed through flowcontroller 3 in order to control its flow rate, and then fed into rawmaterial gas inlet nozzle 2. This raw material gas inlet nozzle 2 isprovided therein with copper filament 26 which has been heated to300-600° C. by supplying an electric current from direct-current powersupply 27 and passing it therethrough. Thus, the aforesaid Cl₂ gas isbrought into efficient contact with copper filament 26 to produce aprecursor 13. When this precursor 13 is introduced into reaction vessel1 through raw material gas inlet nozzle 2, precursor 13 moves downward.

Now, a reducing gas 60 comprising H₂ gas is passed through reducing gasflow controller 6 in order to control its flow rate, and then fed intoreducing gas inlet nozzle 5. This reducing gas inlet nozzle 5 isprovided therein with tungsten filament 23. When tungsten filament 23 isheated to about 1,800° C. by supplying an electric current fromdirect-current power supply 24 and passing it therethrough, an atomicreducing gas 25 comprising atomic hydrogen is produced from reducing gas60. Immediately before precursor 13 arrives at substrate 15, the atomichydrogen is injected into reaction vessel 1 through reducing gas inletnozzle 5. Thus, the aforesaid precursor 13 undergoes a reductionreaction with the atomic hydrogen to form a thin Cu film 62 on substrate15.

The aforesaid raw material gas 55 may comprise any gas containingchlorine. For example, there may be used HCl gas or a mixed gas composedof HCl gas and Cl₂ gas.

Since the above-described method can feed precursor 13 and atomichydrogen simply by use of gas nozzle 5 which permits a relativelyflexible arrangement, a film having an area up to about 100 mm×100 mmcan be stably formed.

Fourth Embodiment

FIG. 4 is a schematic view of a plasma-excited vapor phase growthapparatus 85 for the formation of a thin noble metal film in accordancewith a fourth embodiment of the present invention. Since some componentsof this apparatus 85 have the same structure as those of plasma-excitedvapor phase growth apparatus 51 used in the above-described firstembodiment, these components are designated by the same referencenumerals and the explanation thereof is omitted. The aforesaidplasma-excited vapor phase growth apparatus 85 is characterized by thefact that, in plasma-excited vapor phase growth apparatus 51 inaccordance with the first embodiment, high-frequency electric power isutilized to generate a reducing plasma. Specifically, this apparatus 85is constructed by eliminating rotating magnetic field coil 4, insulatingplate 17, second plasma antenna 18 and second plasma power supply 19from the plasma-excited vapor phase growth apparatus 51 of FIG. 1 andinstead adding an electrode connected to a high-frequency power supply.No modification is made in the components associated with the productionof precursor 13, the feeding of hydrogen gas used as reducing gas 60,and the disposition of substrate 15.

Within reaction vessel 1, the aforesaid plasma-excited vapor phasegrowth apparatus 85 includes a reducing plasma generating electrode 71disposed between perforated plate 12 and heater 16. It also includes ahigh-frequency power supply 76, a matching transformer 75 and anelectric current input terminal 73 which are all disposed on the outsideof reaction vessel 1. These high-frequency power supply 76, matchingtransformer 75 and electric current input terminal 73 are connectedtogether by coaxial cables 74, and electric current input terminal 73and reducing plasma generating electrode 71 are connected together by afeeder 72.

As the aforesaid reducing plasma generating electrode 71, an electrodein the form of a flat plate having a multitude of holes is used so thatthe flux of precursor 13 may not be prevented from traveling towardsubstrate 15. For example, there may be used a circular meshlikeelectrode 77 as illustrated in FIG. 5. This meshlike electrode 77consists of a metal mesh 77 a formed of woven metal wires and disposedinside, and a mesh-holding jig 77 b for fastening the periphery of metalmesh 77 a so as to prevent it from being frayed. This mesh-holding jig77 b comprises, for example, an annulus which is made of the samematerial as that of metal mesh 77 a and used to fasten metal mesh 77 aby sandwiching it from the upper and lower sides.

It is to be understood that the aforesaid reducing plasma generatingelectrode 71 is not limited to meshlike electrode 77, but various typesof electrodes may be used, provided that they have a shape which doesnot prevent the flux of precursor 13 from traveling toward substrate 15.

For example, a ladderlike electrode 79 as illustrated in FIG. 6, acomblike electrode 80 as illustrated in FIG. 7, and a punching boardtype electrode 81 may preferably be used.

The aforesaid ladderlike electrode 79 is formed by arranging a pair ofvertical wires 79 a in parallel and disposing a plurality of horizontalwires 79 b between vertical wires 79 a,79 a. The aforesaid comblikeelectrode 80 is formed by providing two units each consisting of onevertical wire 80 a having a plurality of horizontal wires 80 b attachedthereto, and arranging these two units in interdigitated relationship.The aforesaid punching board type electrode 81 is formed by boring aplurality of small holes 83 in a circular metallic board 82.

In the above-described electrodes, no particular limitation is placed onthe diameter and number of wires constituting metal mesh 77 a, and thepitch of the mesh, in meshlike electrode 77; the diameter, number andspacing of horizontal wires in ladderlike electrode 79; the diameter,number and spacing of vertical and horizontal wires 80 a,80 b, and thenumber of units, in comblike electrode 80; the diameter, number andarrangement of holes bored in board 82 constituting punching board typeelectrode 81; and the degree of opening of the electrode. Accordingly,the shape of the electrode may be suitably chosen according to the typeof the desired reducing action.

An electrically conductive material is used for these electrodes.However, the reaction vessel has an atmosphere of chlorine, it isdesirable to use stainless steel or the like for the purpose ofpreventing corrosion.

The operation of the above-described plasma-excited vapor phase growthapparatus 85 is described below.

The process occurring until precursor 13 is discharged through the holes12 a of perforated plate 12 is the same as described in connection withthe first embodiment. Then, high-frequency power supply 76 applieshigh-frequency electric power to reducing plasma generating electrode 71by way of matching transformer 75 and electric current input terminal73. Thus, a reducing gas plasma 14 comprising hydrogen plasma isgenerated over the entire surface of the aforesaid reducing plasmagenerating electrode 71. When precursor 13 passes through the hydrogenplasma, it undergoes a reduction reaction with atomic hydrogen to form athin Cu film 62 on substrate 15.

Fifth Embodiment

FIG. 9 is a schematic view of a plasma-excited vapor phase growthapparatus 90 for the formation of a thin noble metal film in accordancewith a fifth embodiment of the present invention. This apparatus 90 isbased on the combination of plasma-excited vapor phase growth apparatus85 used in the above-described fourth embodiment (see FIG. 4) with aconvention method for feeding a raw material gas (see FIG. 10). Thecomponents having the same structure are designated by the samereference numerals and the explanation thereof is omitted.

In the aforesaid plasma-excited vapor phase growth apparatus 90, a rawmaterial vessel 121 is connected to a vaporizer 120 via a flowcontroller 103. Moreover, the aforesaid raw material vessel 121 isprovided with a bubbling pipe for producing a vapor of liquid rawmaterial 122 contained therein. Further more, this apparatus 90 isequipped with a device for utilizing high-frequency electric power togenerate a reducing gas plasma 14 and thereby subjecting precursor 13 toa reduction reaction, as illustrated in FIG. 4.

The operation of plasma-excited vapor phase growth apparatus 90 havingthe above-described construction is described below.

First of all, a liquid raw material 122 comprising, for example, copperhexafluoroacetylacetonato-trimethylvinylsilane [Cu(hfac)(tmvs)] iscontained in raw material vessel 121 and a carrier gas comprising He isbubbled therethrough. Liquid raw material 122 is not limited thereto,but may comprise any desired liquid organometallic complex. The rawmaterial evaporated by bubbling is passed through flow controller 103 tocontrol its flow rate, and then fed into vaporizer 120. After theaforesaid raw material is completely vaporized in vaporizer 120, theresulting precursor 113 is introduced into the interior of reactionvessel 1 through perforated plate 112. Now, similarly to the fourthembodiment, a reducing gas plasma 14 comprising hydrogen plasma isgenerated by means of high-frequency electric power. Consequently, whenthe aforesaid precursor 113 passes through the hydrogen plasma,precursor 113 undergoes a reduction reaction to form a thin Cu film 62on substrate 15.

Next, an apparatus and method for the formation of a metal film inaccordance with a sixth embodiment of the present invention is describedwith reference to FIG. 10. FIG. 10 is a schematic side view of theapparatus for the formation of a metal film in accordance with the sixthembodiment of the present invention.

As illustrated in FIG. 10, this apparatus includes a chamber 201 made,for example, of stainless steel and formed into the shape of a box; afirst plasma generating means 202 disposed on the upper side of chamber201; and a second plasma generating means 203 disposed on the lower sideof chamber 201. This apparatus also includes a magnetic field coil 204disposed on the side of chamber 201. First plasma generating means 202consists of a first insulating plate 221 disposed on the top surface ofchamber 201, a first plasma antenna 222 disposed on first insulatingplate 221, and a first power supply 223 for energizing first plasmaantenna 222. Second plasma generating means 203 consists of a secondinsulating plate 224 disposed on the bottom surface of chamber 201, asecond plasma antenna 225 disposed on second insulating plate 225, and asecond power supply 226 for energizing second plasma antenna 225.

Within chamber 201, an inlet vessel 206 is disposed under firstinsulating plate 221, and a raw material gas 205 comprising chlorine gas(Cl₂ gas) is fed into inlet vessel 206. A flow controller 207 and anozzle 208 are connected to the sidewall of inlet vessel 206, and adischarge plate (or metallic plate) 209 made of Copper (Cu) is disposedat the bottom of inlet vessel 206. This discharge plate 209 has amultitude of discharge orifices 210 bored therethrough. A support 211 isdisposed near the bottom of chamber 201 and a substrate 212 is placed onthis support 211. Support 211 is heated to a predetermined temperatureby a heater means (not shown). At the lower end of chamber 201 and belowmagnetic field coil 204, a reducing gas flow controller 214 and areducing gas nozzle 215 are disposed in order to feed a reducing gas 213comprising hydrogen gas (H₂ gas) into the interior of chamber 201.Furthermore, the bottom wall of chamber 201 has an exhaust port 227bored therethrough.

On the other hand, the sidewall of chamber 20 i is provided with afilament type heater 228 serving as a chamber heating means. By using apower supply 229 to energize this heater 228, the sidewall of chamber201 is heated to a predetermined temperature, for example, in the rangeof 200 to 600° C. It is preferable that the upper limit of thepredetermined temperature is not higher than the durable temperature ofchamber 201. Since this embodiment is described in connection withchamber 201 made of stainless steel, the upper temperature limit is setat 600° C. Thus, the upper limit of the predetermined temperature may besuitably determined according to the material of chamber 201.

Even if the precursor (Cu_(x)Cl_(y)) which will be described lateradheres to the sidewall of chamber 201, it will readily be vaporizedbecause the sidewall of chamber 201 is heated to cause a rise in thevapor pressure of the precursor. Consequently, the precursor(Cu_(x)Cl_(y)) is prevented from depositing on the sidewall of chamber201. Since this embodiment is described in connection with dischargeplate 209 made of Cu, the lower limit of the predetermined temperatureis set at 200° C. Thus, the lower limit of the predetermined temperaturemay be suitably determined according to the type of the precursorproduced on the basis of the material of discharge plate 209.

In the above-described apparatus for the formation of a metal film, Cl₂gas is fed into inlet vessel 206. When electromagnetic waves areradiated into inlet vessel 206 by first plasma antenna 222 of firstplasma generating means 202, the Cl₂ gas within inlet vessel 206 isionized to generate Cl₂ gas plasma (raw material gas plasma) 231. ThisCl₂ gas plasma 231 causes an etching reaction of discharge plate 209made of Cu, so that a precursor (Cu_(x)Cl_(y)) 230 is produced. Thisprecursor (Cu_(x)Cl_(y)) 230 is discharged downward through dischargeorifices 210.

On the other hand, H₂ gas is introduced into chamber 201. Whenelectromagnetic waves are radiated into chamber 201 by second plasmaantenna 225 of second plasma generating means 203, the H₂ gas withinchamber 201 is ionized to generate H₂ gas plasma (reducing gas plasma)232. Owing to a rotating magnetic field created by magnetic field coil204, this H₂ gas plasma 232 is densely and uniformly distributed in theneighborhood of the surface of substrate 212.

Immediately before precursor (Cu_(x)Cl_(y)) 230 discharged downwardthrough discharge orifices 210 arrives at substrate 212, it passesthrough H₂ gas plasma 232. While precursor (Cu_(x)Cl_(y)) 230 passesthrough H₂ gas plasma 232 serving as a reducing gas plasma, chlorine isremoved therefrom by a reduction reaction with atomic hydrogen. Theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212.

Since the sidewall of chamber 201 is heated to a predeterminedtemperature (e.g., 200° C.) by heater 228, precursor (Cu_(x)Cl_(y)) 230adhering to the sidewall of chamber 201 will readily be vaporizedbecause of its raised vapor pressure. Consequently, precursor(Cu_(x)Cl_(y)) 230 is prevented from depositing on the sidewall ofchamber 201. It has been confirmed that, if the sidewall of chamber 201has a temperature lower than the predetermined temperature (e.g., 180°C. or so), the vapor pressure of precursor (Cu_(x)Cl_(y)) 230 will notrise sufficiently and, therefore, precursor (Cu_(x)Cl_(y)) 230 willdeposit on the sidewall of chamber 201.

In the above-described apparatus for the formation of a metal film,chlorine gas (Cl₂ gas) is used as an example of raw material gas 205.However, HCl gas may also be used. In this case, HCl gas plasma isgenerated as the raw material gas plasma, but precursor 230 produced bythe etching of discharge plate 209 made of Cu is Cu_(x)Cl_(y).Accordingly, raw material gas 205 may comprise any gas containingchlorine, and a mixed gas composed of HCl gas and Cl₂ gas may also beused. Moreover, the material of discharge plate 209 is not limited toCu, but Ag, Au, Pt, Ti, W and the like may also be used. In this case,precursor 230 comprises a chloride of Ag, Au, Pt, Ti, W or the like, andthe thin film formed on the surface of substrate 212 comprises Ag, Au,Pt, Ti, W or the like.

Since two plasmas, namely Cl₂ gas plasma (raw material gas plasma) 231and H₂ gas plasma (reducing gas plasma) 232, are used in theabove-described apparatus for the formation of a metal film, thereaction efficiency is markedly improved to cause an increase in rate offilm growth. Moreover, since chlorine gas (Cl₂ gas) is used as rawmaterial gas 205 and a hydrogen-containing gas is used as reducing gas213, a marked reduction in cost is achieved. Furthermore, since thereduction reaction can be accelerated independently, the amount ofimpurities (e.g., chlorine) remaining in thin Cu film 233 can beminimized to form a thin Cu film 233 of high quality.

In addition, since the sidewall of chamber 201 is heated to apredetermined temperature by heater 228, precursor (Cu_(x)Cl_(y)) 230adhering to the sidewall of chamber 201 will readily be vaporizedbecause of its raised vapor pressure. Thus, precursor (Cu_(x)Cl_(y)) 230is prevented from depositing on the sidewall of chamber 201.Consequently, the necessity of cleaning the inside of chamber 201periodically can be eliminated to cause an improvement in raw materialefficiency and a reduction in running cost.

Now, an apparatus and method for the formation of a metal film inaccordance with a seventh embodiment of the present invention isdescribed with reference to FIG. 11. FIG. 11 is a schematic side view ofthe apparatus for the formation of a metal film in accordance with theseventh embodiment of the present invention. The same components asthose shown in FIG. 10 are designated by the same reference numerals andthe duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 10, the apparatus for the formation of a metal filmin accordance with the seventh embodiment as illustrated in FIG. 11 doesnot include the chamber heating means comprising filament type heater228 and power supply 229, but includes a discharge plate heating meansfor heating discharge plate 209. Specifically, discharge plate (ormetallic plate) 209 made of Copper (Cu) is provided at the bottom ofinlet vessel 206 through the medium of an insulating member 241. Anauxiliary nozzle 242 for feeding a rare gas comprising He gas isconnected to the sidewall of inlet vessel 206. Thus, He gas is fed intoinlet vessel 206 together with raw material gas 205 comprising chlorinegas (Cl₂ gas). Cl₂ gas and He gas are fed into inlet vessel 206 in aratio of approximately 1:1. A biasing power supply 243 is connected todischarge plate 209, so that a direct-current voltage is applied todischarge plate 209 by biasing power supply 243.

In the above-described apparatus for the formation of a metal film, whenelectromagnetic waves are radiated into inlet vessel 206 by first plasmaantenna 222 of first plasma generating means 202, the Cl₂ gas and He gaswithin inlet vessel 206 are ionized to generate Cl₂—He gas plasma 244.This Cl₂—He gas plasma 244 causes He ions to collide with dischargeplate 209 to which a bias voltage is applied. Thus, discharge plate 209is uniformly heated. As the means for heating discharge plate 209, aheater or other means for heating discharge plate 209 directly may alsobe used in place of the means based on the collision of He ions.

The heating temperature of discharge plate 209 is, for example, in therange of 200 to 800° C. and preferably 600° C. It is preferable that thelower limit of the heating temperature is a temperature at whichprecursor (Cu_(x)Cl_(y)) 230 passing through discharge orifices 210becomes a monomeric compound rather than a polymeric one. When dischargeplate 209 is heated to 600° C., precursor 230 tends td be monomeric CuCland this facilitates the reduction reaction which will be describedlater. The upper limit of the heating temperature depends on thematerial of discharge plate 209. In the case of discharge plate 209 madeof copper (Cu), the upper limit is 800° C. If the heating temperatureexceeds 800° C., discharge plate 209 cannot be used because of itssoftening. Discharge plate 209 can be adjusted to a desired temperatureby controlling the voltage applied to discharge plate 209.

When Cl₂—He gas plasma 244 is generated within inlet vessel 206, the Cl₂gas plasma causes an etching reaction of the heated discharge plate 209made of Cu, so that a monomeric precursor (CuCl) 230 tends to beproduced. The resulting precursor (CuCl) 230 is discharged downwardthrough discharge orifices 210 of discharge plate 209. Immediatelybefore precursor (CuCl) 230 discharged downward through dischargeorifices 210 arrives at substrate 212, it passes through H₂ gas plasma232. Thus, chlorine is removed therefrom by a reduction reaction withatomic hydrogen. The resulting Cu ions are directed onto substrate 212to form a thin Cu film 233 on the surface of substrate 212.

Since precursor 230 discharged downward comprises monomeric CuCl, it canreadily be reduced by atomic hydrogen. Thus, chlorine is removedtherefrom by reduction in a short period of time. Consequently, theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212 in a short period of time. That is,since discharge plate 209 is uniformly heated to a desired temperatureby the collision of He ions, a monomeric precursor (CuCl) 230 which canreadily be reduced is produced. This makes it possible to removechlorine by reduction in a short period of time and thereby improve therate of film growth.

Now, an apparatus and method for the formation of a metal film inaccordance with an eighth embodiment of the present invention isdescribed with reference to FIG. 12. FIG. 12 is a schematic side view ofthe apparatus for the formation of a metal film in accordance with theeighth embodiment of the present invention. The same components as thoseshown in FIGS. 10 and 11 are designated by the same reference numeralsand the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 11, the apparatus for the formation of a metal filmin accordance with the eighth embodiment as illustrated in FIG. 12includes a chamber heating means comprising a filament type heater 228and a power supply 229. That is, this apparatus is equipped with boththe chamber heating means and the discharge plate heating means.

Thus, since the sidewall of chamber 201 is heated to a predeterminedtemperature (e.g., 200° C.) by heater 228, precursor (CuCl) 230 adheringto the sidewall of chamber 201 will readily be vaporized because of itsraised vapor pressure. Consequently, precursor (CuCl) 230 is preventedfrom depositing on the sidewall of chamber 201. Moreover, sinceprecursor 230 discharged downward comprises monomeric CuCl, it canreadily be reduced by atomic hydrogen. Thus, chlorine is removedtherefrom by reduction in a short period of time. Consequently, theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212 in a short period of time.

Accordingly, since the sidewall of chamber 201 is heated to apredetermined temperature by heater 228, precursor (CuCl) 230 adheringto the sidewall of chamber 201 will readily be vaporized because of itsraised vapor pressure. Thus, precursor (CuCl) 230 is prevented fromdepositing on the sidewall of chamber 201. Consequently, the necessityof cleaning the inside of chamber 201 periodically can be eliminated tocause an improvement in raw material efficiency and a reduction inrunning cost. Moreover, since discharge plate 209 is uniformly heated toa desired temperature by the collision of He ions, a monomeric precursor(CuCl) 230 which can readily be reduced is produced. This makes itpossible to remove chlorine by reduction in a short period of time andthereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film inaccordance with a ninth embodiment of the present invention is describedwith reference to FIG. 13. FIG. 13 is a schematic side view of theapparatus for the formation of a metal film in accordance with the ninthembodiment of the present invention. The same components as those shownin FIG. 10 are designated by the same reference numerals and theduplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 10, the apparatus for the formation of a metal filmin accordance with the ninth embodiment as illustrated in FIG. 13 ischaracterized in that an atomic reducing gas 251 id produced in place ofthe reducing gas plasma comprising H₂ gas plasma 232. To this end, thisapparatus includes a reducing gas heating means 252 for heating areducing gas (e.g., H₂ gas) 213 to produce an atomic reducing gas 251,in place of second plasma generating means 203. This reducing gasheating means 252 consists of a reducing gas flow controller 214, areducing gas nozzle 215 attached thereto, and tungsten filament 253disposed within reducing gas nozzle 215. The ends of tungsten filament215 are connected to a direct-current power supply 254.

In the above-described apparatus for the formation of a metal film, Cl₂gas is fed into inlet vessel 206. When electromagnetic waves areradiated into inlet vessel 206 by first plasma antenna 222 of firstplasma generating means 202, the Cl₂ gas within inlet vessel 206 isionized to generate Cl₂ gas plasma (raw material gas plasma) 231. ThisCl₂ gas plasma 231 causes an etching reaction of discharge plate 209made of Cu, so that a precursor (Cu_(x)Cl_(y)) 230 is produced. Thisprecursor (Cu_(x)Cl_(y)) 230 is discharged downward through dischargeorifices 210.

Immediately before precursor (Cu_(x)Cl_(y)) 230 arrives at substrate212, a reducing gas 213 comprising H₂ gas is passed through reducing gasflow controllers 214 in order to control its flow rate, and tungstenfilament 253 is heated to 1,800° C. by means of direct-current powersupply 254. As a result of the hearing of tungsten filament 253, anatomic reducing gas 251 (atomic hydrogen) is produced and injected intochamber 201 through reducing gas inlet nozzle 215. Consequently,precursor (Cu_(x)Cl_(y)) 230 discharged downward through dischargeorifices 210 passes through atomic reducing gas 251 immediately beforearriving at substrate 212. Thus, chlorine is removed from precursor(Cu_(x)Cl_(y)) 230 by a reduction reaction with atomic hydrogen. Theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212.

Since the sidewall of chamber 201 is heated to a predeterminedtemperature (e.g., 200° C.) by heater 228, precursor (Cu_(x)Cl_(y)) 230adhering to the sidewall of chamber 201 will readily be vaporizedbecause of its raised vapor pressure. Consequently, precursor(Cu_(x)Cl_(y)) 230 is prevented from depositing on the sidewall ofchamber 201.

In the above-described apparatus for the formation of a metal film,since chlorine gas (Cl₂ gas) is used as raw material gas 205 and ahydrogen-containing gas is used as reducing gas 213, a marked reductionin cost is achieved. Moreover, since the reduction reaction can beaccelerated independently, the amount of impurities (e.g., chlorine)remaining in thin Cu film 233 can be minimized to form a thin Cu film233 of high quality. Furthermore, since atomic reducing gas 251comprising atomic hydrogen can be fed simply by use of reducing gasnozzle 215 which permits a relatively flexible arrangement, a filmhaving a large area (e.g., 50 mm×50 mm) can be stably formed.

In addition, since the sidewall of chamber 201 is heated to apredetermined temperature by heater 228, precursor (Cu_(x)Cl_(y)) 230adhering to the sidewall of chamber 201 will readily be vaporizedbecause of its raised vapor pressure. Thus, precursor (Cu_(x)Cl_(y)) 230is prevented from depositing on the sidewall of chamber 201.Consequently, the necessity of cleaning the inside of chamber 201periodically can be eliminated to cause an improvement in raw materialefficiency and a reduction in running cost.

Now, an apparatus and method for the formation of a metal film inaccordance with a tenth embodiment of the present invention is describedwith reference to FIG. 14. FIG. 14 is a schematic side view of theapparatus for the formation of a metal film in accordance with the tenthembodiment of the present invention. The same components as those shownin FIG. 13 are designated by the same reference numerals and theduplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 13, the apparatus for the formation of a metal filmin accordance with the tenth embodiment as illustrated in FIG. 14 doesnot include the chamber heating means comprising filament type heater228 and power supply 229, but includes a discharge plate heating meansfor heating discharge plate 209. Specifically, discharge plate (ormetallic plate) 209 made of Copper (Cu) is provided at the bottom ofinlet vessel 206 through the medium of an insulating member 241. Anauxiliary nozzle 242 for feeding a rare gas comprising He gas isconnected to the sidewall of inlet vessel 206. Thus, He gas is fed intoinlet vessel 206 together with raw material gas 205 comprising chlorinegas (Cl₂ gas). Cl₂ gas and He gas are fed into inlet vessel 206 in aratio of approximately 1:1. A biasing power supply 243 is connected todischarge plate 209, so that a direct-current voltage is applied todischarge plate 209 by biasing power supply 243.

In the above-described apparatus for the formation of a metal film, whenelectromagnetic waves are radiated into inlet vessel 206 by first plasmaantenna 222 of first plasma generating means 202, the Cl₂ gas and He gaswithin inlet vessel 206 are ionized to generate Cl₂—He gas plasma 244.This Cl₂—He gas plasma 244 causes He ions to collide with dischargeplate 209 to which a bias voltage is applied. Thus, discharge plate 209is uniformly heated. As the means for heating discharge plate 209, aheater or other means for heating discharge plate 209 directly may alsobe used in place of the means based on the collision of He ions.

The heating temperature of discharge plate 209 is, for example, in therange of 200 to 800° C. and preferably 600° C. It is preferable that thelower limit of the heating temperature is a temperature at whichprecursor (Cu_(x)Cl_(y)) 230 passing through discharge orifices 210becomes a monomeric compound rather than a polymeric one. When dischargeplate 209 is heated to 600° C., precursor 230 tends to be monomeric CuCland this facilitates the reduction reaction which will be describedlater. The upper limit of the heating temperature depends on thematerial of discharge plate 209. In the case of discharge plate 209 madeof copper (Cu), the upper limit is 800° C. If the heating temperatureexceeds 800° C., discharge plate 209 cannot be used because of itssoftening. Discharge plate 209 can be adjusted to a desired temperatureby controlling the voltage applied to discharge plate 209.

When Cl₂—He gas plasma 244 is generated within inlet vessel 206, the Cl₂gas plasma causes an etching reaction of the heated discharge plate 209made of Cu, so that a monomeric precursor (CuCl) 230 tends to beproduced. The resulting precursor (CuCl) 230 is discharged downwardthrough discharge orifices 210 of discharge plate 209. Immediatelybefore precursor (CuCl) 230 discharged downward through dischargeorifices 210 arrives at substrate 212, it passes through atomic reducinggas 251. Thus, chlorine is removed from precursor (CuCl) 230 by areduction reaction with atomic hydrogen. The resulting Cu ions aredirected onto substrate 212 to form a thin Cu film 233 on the surface ofsubstrate 212.

Since precursor 230 discharged downward comprises monomeric CuCl, it canreadily be reduced by atomic hydrogen. Thus, chlorine is removedtherefrom by reduction in a short period of time. Consequently, theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212 in a short period of time. That is,since discharge plate 209 is uniformly heated to a desired temperatureby the collision of He ions, a monomeric precursor (CuCl) 230 which canreadily be reduced is produced. This makes it possible to removechlorine by reduction in a short period of time and thereby improve therate of film growth.

Now, an apparatus and method for the formation of a metal film inaccordance with an eleventh embodiment of the present invention isdescribed with reference to FIG. 15. FIG. 15 is a schematic side view ofthe apparatus for the formation of a metal film in accordance with theeleventh embodiment of the present invention. The same components asthose shown in FIGS. 13 and 14 are designated by the same referencenumerals and the duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 14, the apparatus for the formation of a metal filmin accordance with the eleventh embodiment as illustrated in FIG. 15includes a chamber heating means comprising a filament type heater 228and a power supply 229. That is, this apparatus is equipped with boththe chamber heating means and the discharge plate heating means.

Thus, since the sidewall of chamber 201 is heated to a predeterminedtemperature (e.g., 200° C.) by heater 228, precursor (CuCl) 230 adheringto the sidewall of chamber 201 will readily be vaporized because of itsraised vapor pressure. Consequently, precursor (CuCl) 230 is preventedfrom depositing on the sidewall of chamber 201. Moreover, sinceprecursor 230 discharged downward comprises monomeric CuCl, it canreadily be reduced by atomic hydrogen. Thus, chlorine is removedtherefrom by reduction in a short period of time. Consequently, theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212 in a short period of time.

Accordingly, since the sidewall of chamber 201 is heated to apredetermined temperature by heater 228, precursor (CuCl) 230 adheringto the sidewall of chamber 201 will readily be vaporized because of itsraised vapor pressure. Thus, precursor (CuCl) 230 is prevented fromdepositing on the sidewall of chamber 201. Consequently, the necessityof cleaning the inside of chamber 201 periodically can be eliminated tocause an improvement in raw material efficiency and a reduction inrunning cost. Moreover, since discharge plate 209 is uniformly heated toa desired temperature by the collision of He ions, a monomeric precursor(CuCl) 230 which can readily be reduced is produced. This makes itpossible to remove chlorine by reduction in a short period of time andthereby improve the rate of film growth.

Now, an apparatus and method for the formation of a metal film inaccordance with a twelfth embodiment of the present invention isdescribed with reference to FIG. 16. FIG. 16 is a schematic side view ofthe apparatus for the formation of a metal film in accordance with thetwelfth embodiment of the present invention. The same components asthose shown in FIG. 13 are designated by the same reference numerals andthe duplicate explanation thereof is omitted.

When compared with the apparatus for the formation of a metal film asillustrated in FIG. 13, the apparatus for the formation of a metal filmin accordance with the twelfth embodiment as illustrated in FIG. 16 ischaracterized in that a precursor (Cu_(x)Cl_(y)) 230 is injected intochamber 201 from a nozzle 208 of a raw material gas heating means 261,instead of generating Cl₂ gas plasma 231 within inlet vessel 206 toproduce precursor (Cu_(x)Cl_(y)) 230. Raw material gas heating means 261consists of a flow controller 207, a nozzle 208 attached thereto, and acopper filament 262 comprising several turns of copper wire and disposedwithin nozzle 208. The ends of copper filament 262 are connected to adirect-current power supply 263. Copper filament 262 is heated to300-600° C. by direct-current power supply 263.

In the above-described apparatus for the formation of a metal film, araw material gas comprising Cl₂ gas is passed through flow controller207 in order to control its flow rate, and then fed into nozzle 208.Since nozzle 208 is provided therein with copper filament 262 which hasbeen heated to 300-600° C. by direct-current power supply 263, thecontact of Cl₂ gas with the heated copper filament 262 produces aprecursor (Cu_(x)Cl_(y)) 230. When this precursor (Cu_(x)Cl_(y)) 230 isintroduced into chamber 201 through nozzle 208, precursor (Cu_(x)Cl_(y))230 moves downward.

Immediately before precursor (Cu_(x)Cl_(y)) 230 arrives at substrate212, a reducing gas 213 comprising H₂ gas is passed through reducing gasflow controllers 214 in order to control its flow rate, and tungstenfilament 253 is heated to 1,800° C. by means of direct-current powersupply 254. As a result of the hearing of tungsten filament 253, anatomic reducing gas 251 (atomic hydrogen) is produced and injected intochamber 201 through reducing gas inlet nozzle 215. Consequently,precursor (Cu_(x)l_(y)) 230 discharged downward through dischargeorifices 210 passes through atomic reducing gas 251 immediately beforearriving at substrate 212. Thus, chlorine is removed from precursor(Cu_(x)Cl_(y)) 230 by a reduction reaction with atomic hydrogen. Theresulting Cu ions are directed onto substrate 212 to form a thin Cu film233 on the surface of substrate 212.

Since the sidewall of chamber 201 is heated to a predeterminedtemperature (e.g., 200° C.) by heater 228 as described previously,precursor (Cu_(x)Cl_(y)) 230 adhering to the sidewall of chamber 201will readily be vaporized because of its raised vapor pressure.Consequently, precursor (Cu_(x)Cl_(y)) 230 is prevented from depositingon the sidewall of chamber 201.

In the above-described apparatus for the formation of a metal film,since precursor (Cu_(x)Cl_(y)) 230 can be fed simply by use of nozzle208 which permits a relatively flexible arrangement, and atomic hydrogencan be fed simply by use of reducing gas nozzle 215 which permits arelatively flexible arrangement, a film having a large area (e.g., 100mm×100 mm) can be very stably formed.

Moreover, since the sidewall of chamber 201 is heated to a predeterminedtemperature by heater 228, precursor (CuCl) 230 adhering to the sidewallof chamber 201 will readily be vaporized because of its raised vaporpressure. Thus, precursor (CuCl) 230 is prevented from depositing on thesidewall of chamber 201. Consequently, the necessity of cleaning theinside of chamber 201 periodically can be eliminated to cause animprovement in raw material efficiency and a reduction in running cost.

FIG. 17 is a schematic sectional view of an apparatus for the vaporphase growth of a thin copper film in accordance with a thirteenthembodiment of the present invention, and FIG. 18 is a plan view of adischarge plate made of copper and incorporated into the vapor phasegrowth apparatus of FIG. 17.

Within a reaction vessel 302 formed into the shape of a box and providedwith an exhaust tube 301 at the bottom, a flat plate type heater 303 isdisposed and a substrate to be treated is placed thereon. An evacuationmeans (not shown), such as a vacuum pump, is connected to the other endof the aforesaid exhaust tube 301. An inlet vessel 306 in the form of aclosed-end cylinder, which has a copper discharge plate 305 having aplurality of discharge orifices 304 bored therethrough at the bottom, issuspended in the upper part of the aforesaid reaction vessel 302. Theaforesaid copper discharge plate 305 is provided with a circulation pipe307 serving as a temperature control means for passing a heating medium(e.g., heated air) or a cooling medium (e.g., cooled air) therethrough.As illustrated in FIG. 18, this circulation pipe 307 is built in theaforesaid copper discharge plate 305 so that it lies in parallel withthe surfaces of discharge plate 305 and runs in a serpentine manner.

A raw material gas feed pipe 308 for feeding chlorine or hydrogenchloride extends from the outside through the sidewall of the aforesaidreaction vessel 302 and the sidewall of the aforesaid inlet vessel 306,and is inserted into the interior of the aforesaid inlet vessel 306. Aflow controller 309 is installed in a portion of the aforesaid rawmaterial gas feed pipe 308 which is located on the outside of theaforesaid reaction vessel 302. A first plasma generator 310 is disposedon the top surface of the aforesaid reaction vessel 302 to which theaforesaid inlet vessel 306 is attached. This first plasma generator 310consists of an insulating plate 311 disposed on the top surface of theaforesaid reaction vessel 302 so as to cover the aforesaid inlet vessel306, a first plasma antenna 312 disposed on this insulating plate 311,and a first plasma power supply 313 connected to this first plasmaantenna 312.

A water partial pressure gauge 315 having two sensing elements 314 a and314 b is disposed on the outside of the aforesaid reaction vessel 302.One sensing elements 314 a extends through the sidewall of the aforesaidreaction vessel 302 and the sidewall of the aforesaid inlet vessel 306,and is inserted into the interior of the aforesaid inlet vessel 306. Theother sensing elements 314 b extends through the sidewall of theaforesaid reaction vessel 302 and is inserted into the interior of theaforesaid reaction vessel 302. The aforesaid water partial pressuregauge 341 is used to measure the partial pressure of water when theaforesaid reaction vessel 302 and the aforesaid inlet vessel 306 areevacuated prior to film formation. A hydrogen feed pipe 316 for feedinga reducing gas (e.g., hydrogen) extends from the outside through thelower sidewall of the aforesaid reaction vessel 302 and is inserted intothe interior of the aforesaid reaction vessel 302. A flow controller 317is installed in a portion of the aforesaid hydrogen feed pipe 316 whichis located on the outside of the aforesaid reaction vessel 302. A secondplasma generator 318 is disposed at the bottom of the aforesaid reactionvessel 302. This second plasma generator 318 consists of an insulatingplate 319 disposed on the bottom surface of the aforesaid reactionvessel 302, a second plasma antenna 320 disposed on the underside ofthis insulating plate 319, and a second plasma power supply 321connected to the underside of this second plasma antenna 320. A rotatingmagnetic field coil 322 is disposed around the lower sidewall of theaforesaid reaction vessel 302 with a desired space left therebetween.This rotating magnetic field coil 322 acts on the hydrogen plasmagenerated above the aforesaid heater 303 of the aforesaid reactionvessel 302 as will be described later so that the hydrogen plasma may bedensely distributed in the neighborhood of the surface of the substrateto be treated which is placed on the aforesaid heater 303.

Now, the method for forming a thin copper film by using theabove-described apparatus for the vapor phase growth of a thin copperfilm as illustrated in FIGS. 17 and 18 is described below.

First of all, a substrate 323 to be treated is placed on the flat platetype heater 303 of reaction vessel 302. An evacuation means (not shown)is operated to remove the gas (air) within the aforesaid reaction vessel302 and inlet vessel 306 through exhaust tube 301 until a predetermineddegree of vacuum is reached.

In this evacuation step, the partial pressures of water within theaforesaid reaction vessel 302 and inlet vessel 306 are measured by meansof water partial pressure gauge 315 to confirm that the partialpressures of water remain constant. After the partial pressures of waterhave been confirmed, hydrogen is fed into the aforesaid reaction vessel302 through hydrogen feed pipe 316. The flow rate of this hydrogen iscontrolled by means of flow controller 317 installed in the aforesaidhydrogen feed pipe 316. The second plasma power supply 321 of secondplasma generator 318 is operated to apply, for example, high-frequencyelectric power to the aforesaid second plasma antenna 320 and therebygenerate hydrogen plasma 324 above and near the aforesaid substrate 323to be treated. Under the action of a rotating magnetic field created byrotating magnetic field coil 322 disposed on the outside of theaforesaid reaction vessel 302, the aforesaid hydrogen plasma 324 isdensely distributed in the neighborhood of the surface of the aforesaidsubstrate 323 to be treated.

Then, a raw material gas comprising, for example, chlorine (Cl₂) is fedinto the aforesaid inlet vessel 306 through raw material gas feed pipe308. The flow rate of this chlorine is controlled by means of flowcontroller 309 installed in the aforesaid raw material gas feed pipe308. A heating medium (e.g., heated air) heated to a predeterminedtemperature is supplied to and circulated through the circulation pipe307 of copper discharge plate 305. Thus, copper discharge plate 305 isheated to a predetermined temperature. After heating copper dischargeplate 305, the first plasma power supply 313 of first plasma generator310 is operated to apply, for example, high-frequency electric power tothe aforesaid first plasma antenna 312 and thereby generate chlorineplasma 325 within the aforesaid inlet vessel 306. If the temperature ofthe aforesaid discharge plate 305 is excessively raised with thegeneration of chlorine plasma 325, the aforesaid discharge plate 305 maybe adjusted to a desired temperature by supplying a cooling medium tothe aforesaid circulation pipe 307′ in place of the aforesaid heatingmedium.

As a result of the above-described generation of chlorine plasma 324,activated chlorine in this plasma 324 reacts with copper discharge plate305 which has been heated to a predetermined temperature by supplyingand circulating a heating medium through the aforesaid circulation pipe307. Thus, a precursor (Cu_(x)Cl_(y)) comprising copper chloride isproduced. As shown by arrows in FIG. 17, the resulting precursor(Cu_(x)Cl_(y)) is discharged into the aforesaid reaction vessel 302through the plurality of discharge orifices 304 of the aforesaiddischarge plate 305. Immediately before the discharged precursor arrivesat substrate 323 to be treated which is placed on flat plate type heater303, it passes through the aforesaid hydrogen plasma 324 and undergoes areduction reaction with atomic hydrogen in this hydrogen plasma 324.Consequently, copper produced by the reduction reaction of the precursor(Cu_(x)Cl_(y)) with atomic hydrogen grows on the aforesaid substrate 323to be treated, resulting in the formation of a thin copper film.

Thus, according to the thirteenth embodiment, an inexpensive copperchloride precursor (Cu_(x)Cl_(y)) useful as a raw material for the vaporphase growth of copper can be produced by feeding inexpensive chlorineinto inlet vessel 306 having copper discharge plate 305 at the bottomthrough raw material feed pipe 308, generating chlorine plasma 325within the aforesaid inlet vessel 306 by means of first plasma generator310, and reacting activated chlorine in this plasma 325 with theaforesaid copper discharge plate 305. Moreover, since the reaction ofactivated chlorine in plasma 325 with the aforesaid copper dischargeplate 305 can be accelerated by supplying and circulating a heatingmedium through circulation pipe 307 built in the aforesaid copperdischarge plate 305 and thus heating the aforesaid copper dischargeplate 305 to a predetermined temperature, the amount of precursor(Cu_(x)Cl_(y)) produced can be increased.

The precursor so produced is discharged into reaction vessel 302 throughthe plurality of discharge orifices 304 of the aforesaid discharge plate305, and subjected to a reduction reaction with atomic hydrogen while itpasses through hydrogen plasma 324 previously generated within theaforesaid reaction vessel 302.

Thus, a thin copper film can be rapidly formed on the aforesaidsubstrate 323 to be treated, because copper can grow at a relativelyhigher rate than in thermal decomposition processes.

Moreover, copper discharge plate 305 begins to react with activatedchlorine in the aforesaid chlorine plasma 325 when copper dischargeplate 305 is heated to a certain temperature by supplying andcirculating a heating medium through circulation pipe 307 built incopper discharge plate 305. Consequently, the pressure of the precursordischarged through the plurality of discharge orifices 304 of theaforesaid copper discharge plate (i.e., the discharge pressure) can bestabilized.

Moreover, the same type of precursor (Cu_(x)Cl_(y)) is produced. As aresult, the rate of copper film growth on the aforesaid substrate 323 tobe treated can be stabilized, so that a thin copper film having adesired thickness can be reproducibly formed on the aforesaid substrate323 to be treated.

Furthermore, not only the aforesaid precursor (Cu_(x)Cl_(y)) undergoes areduction reaction with atomic hydrogen while it passes through hydrogenplasma 324, and causes the vapor phase growth of copper on the surfaceof the aforesaid substrate 323 to be treated, but also atomic hydrogenin hydrogen plasma 324 exerts a reducing action on the growing copperfilm. Consequently, a thin copper film containing little residual can beformed.

In the above-described thirteenth embodiment, a circulation pipe forpassing a heating medium or cooling medium therethrough is used as thetemperature control means for the aforesaid copper discharge plate.However, the present invention is not limited thereto, but the aforesaidcopper discharge plate may be provided with a combination of a heaterand a circulation pipe for a cooling medium.

Although chlorine is used as the raw material gas in the above-describedthirteenth embodiment, a copper chloride precursor (Cu_(x)Cl_(y)) canalso be produced by using hydrogen chloride.

Although atomic hydrogen is produced by converting hydrogen into aplasma in the above-described thirteenth embodiment, atomic hydrogen mayalso be produced by installing a heater (e.g., a tungsten filament) forheating hydrogen fed into the aforesaid reaction vessel.

FIG. 19 is a schematic sectional view of an apparatus for the vaporphase growth of a thin copper film in accordance with a fourteenthembodiment of the present invention, FIG. 20(A) is a longitudinalsectional view of a spiral tube incorporated into the vapor phase growthapparatus of FIG. 19, FIG. 20(B) is a transverse sectional view of thisspiral tube, FIG. 21(A) is a longitudinal sectional view of another typeof spiral tube incorporated into the vapor phase growth apparatus ofFIG. 19, and FIG. 21(B) is a transverse sectional view of this spiraltube.

Within a reaction vessel 332 formed into the shape of a box and providedwith an exhaust tube 331 at the bottom, a flat plate type heater 333 isdisposed and a substrate to be treated is placed thereon. An evacuationmeans (not shown), such as a vacuum pump, is connected to the other endof the aforesaid exhaust tube 331.

A raw material gas feed pipe 334 for feeding chlorine or hydrogenchloride extends from the outside through the sidewall of the aforesaidreaction vessel 332 and is inserted into the upper part of the aforesaidreaction vessel 332. A flow controller 335 is installed in a portion ofthe aforesaid raw material gas feed pipe 334 which is located on theoutside of the aforesaid reaction vessel 332. The aforesaid reactionvessel 332 includes a spiral tube 336 having a raw material gas flowpassage whose inner surface is made of copper, and equipped with aheating element. Its upper end is connected to the end of the aforesaidraw material gas feed pipe 334 which is located on the inside of theaforesaid reaction vessel 332. This spiral tube 336 has, for example, adual tubular structure consisting of an outer tube 337 and an innercopper tube 338 inserted into this outer tube 337 and connected to theaforesaid raw material gas feed pipe 334, as illustrated in FIG. 20. Theaforesaid raw material gas is made to flow through the aforesaid innercopper tube 338, and a heating medium (e.g., heated air) is made to flowthrough the annular space between the aforesaid outer tube 337 and theaforesaid inner copper tube 338. A heating medium feed pipe (not shown),which extends through a wall of the aforesaid reaction vessel 332, isconnected to a portion of outer tube 337 of spiral tube 336 which islocated in the neighborhood of its joint with the aforesaid raw materialgas feed pipe 334, and used to feed a heating medium into the annularspace between the aforesaid outer tube 337 and the aforesaid innercopper tube 338. Moreover, a heating medium discharge pipe (not shown),which extends through a wall of the aforesaid reaction vessel 332, isconnected to a portion of outer tube 337 which is located in theneighborhood of the lower end of the aforesaid spiral tube 336, and usedto discharge the heating medium fed into the aforesaid annular space tothe outside.

A precursor discharge member 339 is disposed within the aforesaidreaction vessel 332 in such a way that the aforesaid precursor dischargemember 339 lies under the aforesaid spiral tube 336 and its upper partis connected to the aforesaid spiral tube 336.

A water partial pressure gauge 341 having two sensing elements 340 a and340 b is disposed on the outside of the aforesaid reaction vessel 332.One sensing elements 340 a extends through the sidewall of the aforesaidreaction vessel 332 and the outer tube 337 and inner copper tube 338 ofthe aforesaid spiral tube 336, and is inserted into the interior of theaforesaid inner copper tube 338. The other sensing elements 340 bextends through the sidewall of the aforesaid reaction vessel 332 and isinserted into the interior of the aforesaid reaction vessel 332. Theaforesaid water partial pressure gauge 341 is used to measure thepartial pressure of water when the aforesaid reaction vessel 332 and theinner copper tube 338 of the aforesaid spiral tube 336 are evacuatedprior to film formation.

A hydrogen feed pipe 342 for feeding a reducing gas (e.g., hydrogen)extends from the outside through the lower sidewall of the aforesaidreaction vessel 332 and is inserted into the interior of the aforesaidreaction vessel 332. A flow controller 343 is installed in a portion ofthe aforesaid hydrogen feed pipe 342 which is located on the outside ofthe aforesaid reaction vessel 332. A plasma generator 344 is disposed atthe bottom of the aforesaid reaction vessel 332. This plasma generator344 consists of an insulating plate 345 disposed on the bottom surfaceof the aforesaid reaction vessel 332, a plasma antenna 346 disposed onthe underside of this insulating plate 345, and a plasma power supply347 connected to the underside of this plasma antenna 346. A rotatingmagnetic field coil 348 is disposed around the lower sidewall of theaforesaid reaction vessel 332 with a desired space left therebetween.This rotating magnetic field coil 348 acts on the hydrogen plasmagenerated above the aforesaid heater 333 of the aforesaid reactionvessel 332 as will be described later so that the hydrogen plasma may bedensely distributed in the neighborhood of the surface of the substrateto be treated which is placed on the aforesaid heater 333.

Now, the method for forming a thin copper film by using theabove-described apparatus for the vapor phase growth of a thin copperfilm as illustrated in FIGS. 19 and 20 is described below.

First of all, a substrate 349 to be treated is placed on the flat platetype heater 333 of reaction vessel 332. An evacuation means (not shown)is operated to remove the gas (air) within the aforesaid reaction vessel332 and the inner copper tube 338 of spiral tube 336 through exhausttube 331 until a predetermined degree of vacuum is reached.

In this evacuation step, the partial pressures of water within theaforesaid reaction vessel 332 and the inner copper tube 338 of spiraltube 336 are measured by means of water partial pressure gauge 341 toconfirm that the partial pressures of water remain constant. After thepartial pressures of water have been confirmed, hydrogen is fed into theaforesaid reaction vessel 332 through hydrogen feed pipe 342. The flowrate of this hydrogen is controlled by means of flow controller 343installed in the aforesaid hydrogen feed pipe 342. The plasma powersupply 347 of plasma generator 344 is operated to apply, for example,high-frequency electric power to the aforesaid plasma antenna 346 andthereby generate hydrogen plasma 350 above and near the aforesaidsubstrate 349 to be treated. Under the action of a rotating magneticfield created by rotating magnetic field coil 348 disposed on theoutside of the aforesaid reaction vessel 332 the aforesaid hydrogenplasma 350 is densely distributed in the neighborhood of the surface ofthe aforesaid substrate 349 to be treated.

Then, a raw material gas comprising, for example, chlorine (Cl₂) is fedinto the inner copper tube 338 of the aforesaid spiral tube 336 throughraw material gas feed pipe 334. The flow rate of this chlorine iscontrolled by means of flow controller 335 installed in the aforesaidraw material gas feed pipe 334. A heating medium (e.g., heated air)heated to a predetermined temperature is supplied from the outside ofthe aforesaid reaction vessel 332 through a heating medium feed pipe(not shown) to the annular space between the outer tube 337 and innercopper tube 338 of the aforesaid spiral tube 336. This heating medium isdischarged to the outside through a heating medium discharge pipe (notshown). Thus, the inner copper tube 338 of the aforesaid spiral tube 336is heated to a predetermined temperature, so that the aforesaid innercopper tube 338 reacts with the chlorine (Cl₂) flowing therethrough toproduce a precursor (Cu_(x)Cl_(y)) comprising copper chloride.

As shown by arrows in FIG. 19, the resulting precursor (Cu_(x)Cl_(y)) isdischarged into the aforesaid reaction vessel 332 from precursordischarge member 339. Immediately before the discharged precursorarrives at substrate 349 to be treated which is placed on flat platetype heater 333, it passes through the aforesaid hydrogen plasma 350 andundergoes a reduction reaction with atomic hydrogen in this hydrogenplasma 350. Consequently, copper produced by the reduction reaction ofthe precursor (Cu_(x)Cl_(y)) with atomic hydrogen grows on the aforesaidsubstrate 349 to be treated, resulting in the formation of a thin copperfilm.

Thus, according to the fourteenth embodiment, an inexpensive copperchloride precursor (Cu_(x)Cl_(y)) useful as a raw material for the vaporphase growth of copper can be produced by feeding inexpensive chlorineinto the inner copper tube 338 of spiral tube 336, passing a heatingmedium through the annular space between the outer tube 337 and innercopper tube 338 of the aforesaid spiral tube 336 to heat the aforesaidinner copper tube 338, and thus reacting chlorine with the aforesaidinner copper tube 338.

The precursor so produced is discharged into reaction vessel 332 fromprecursor discharge member 339, and subjected to a reduction reactionwith atomic hydrogen while it passes through hydrogen plasma 350previously generated within the aforesaid reaction vessel 332. Thus, athin copper film can be rapidly formed on the aforesaid substrate 349 tobe treated, because copper can grow at a relatively higher rate than inthermal decomposition processes.

Moreover, the aforesaid inner copper tube 338 begins to react withchlorine flowing through this inner copper tube 338 when inner coppertube 338 is heated to a certain temperature by passing a heating mediumthrough the annular space between the outer tube 337 and inner coppertube 338 of the aforesaid spiral tube 336. Consequently, the pressure ofthe precursor discharged from the aforesaid precursor discharge member339 (i.e., the discharge pressure) can be stabilized. Moreover, the sametype of precursor (Cu_(x)Cl_(y)) is produced. As a result, the rate ofcopper film growth on the aforesaid substrate 349 to be treated can bestabilized, so that a thin copper film having a desired thickness can bereproducibly formed on the aforesaid substrate 349.

Furthermore, not only the aforesaid precursor (Cu_(x)Cl_(y)) undergoes areduction reaction with atomic hydrogen while it passes through hydrogenplasma 350, and causes the vapor phase growth of copper on the surfaceof the aforesaid substrate 349 to be treated, but also atomic hydrogenin hydrogen plasma 350 exerts a reducing action on the growing copperfilm. Consequently, a thin copper film containing little residualimpurity (e.g., chlorine) and hence having a good film quality can beformed.

In the above-described fourteenth embodiment, the spiral tube has a dualtubular structure and the aforesaid inner copper tube is heated bysupplying a heating medium to the annular space between the outer tubeand inner copper tube of the aforesaid spiral tube. However, the presentinvention is not limited to the above-described structure. For example,as illustrated in FIG. 21, spiral tube 336 may have a structureconsisting of a copper tube 351 and a tubular heater 353 disposed aroundcopper tube 351 with a tubular insulator 352 interposed therebetween.Thus, the aforesaid copper tube 351 can be heated to a predeterminedtemperature by the aforesaid tubular heater 353.

Although chlorine is used as the raw material gas in the above-describedfourteenth embodiment, a copper chloride precursor (Cu_(x)Cl_(y)) canalso be produced by using hydrogen chloride.

Although atomic hydrogen is produced by converting hydrogen into aplasma in the above-described fourteenth embodiment, atomic hydrogen mayalso be produced by installing a heater or other means for heatinghydrogen fed into the aforesaid reaction vessel.

1. An apparatus for forming a metal film, comprising: a reaction vesselconfigured to house a substrate; a precursor feeding device for bubblinga carrier gas through a liquid organometallic complex, vaporizing theorganometallic complex, producing a precursor from the vaporizedorganometallic complex, and feeding the precursor into the reactionvessel; a rotating magnetic field generator for creating a rotatingmagnetic field in a space above the substrate; and a second plasmagenerator for generating a plasma from a reducing gas fed into thereaction vessel.
 2. An apparatus for forming a metal film, comprising: areaction vessel configured to house a substrate; a precursor feedingdevice for bubbling a carrier gas through a liquid organometalliccomplex, vaporizing the organometallic complex, producing a precursorfrom the vaporized organometallic complex, and feeding the precursorinto the reaction vessel; and an electrode for generating a plasma froma reducing gas fed into the reaction vessel by applying high-frequencyelectric power thereto.